For example I want to find all titles which have () in title as some have wrong metadata - series are in the title and not in series.
Title is like:
Title (series)
I want:
Title

But first I need to find these books.

The search

Code:

title:"~\(.*\)"

will find all titles containing an open parenthesis followed by some number of characters then a closing parenthesis. The ~ character tells calibre that the search uses regular expressions. Regexp searches can match all sorts of patterns. See The Search Interface in calibre's documentation for more information on what kinds of searches are supported.